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Cravotta, C. A., III, Watzlaf, G. R., Naftz, D. L., Morrison, S. J., Fuller, C. C., & Davis, J. A. (2002). Design and performance of limestone drains to increase pH and remove metals from acidic mine drainage Handbook of groundwater remediation using permeable reactive barriers; applications to radionuclides, trace metals, and nutrients.. Amsterdam: Academic Press.
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Davies, G. J., Holmes, M., Wireman, M., King, K., Gertson, J. N., & Stefanic, J. M. (2001). Water tracing at scales of hours to decades as an aid to estimating hydraulic characteristics of the Leadville Mine drainage tunnel.
Abstract: The Leadville Mine Drainage Tunnel (LMDT) is a 3.3 kilometer structure that was constructed in the complicated geology of the Leadville mine district in the 1940's. Discharge from the LMDT is impacted by heavy metals and is treated at a plant built in 1992 operated by the United States Bureau of Reclamation. On the surface waste rock and other remnants of the mining operations litter the landscape and this material is exposed to precipitation. As a result of contact with this material, surface water often has pH of less than 3 and its containment and disposal is necessary before it impacts surface drainage and the nearby Arkansas River. Using a borehole drilled into the mine workings the U.S. EPA has devised a plan in which the impacted water is contained on the surface which then can be discharged into the mine workings to discharge from the LMDT and be treated. The percentage of water discharging from the mining district along the drainage tunnel is unknown, and since there is no access, information about the condition of the tunnel with regards to blockages is also relatively obscure. Application of quantitative water tracing using fluorescent dyes was used to model the flow parameters at the scale of hours in the tunnel and evaluate the likelihood of blockages. Because the tunnel has intersected several lithologies and faults, other locations such as discharging shafts, adits and surface streams that could be hydraulically connected to the LMDT were also monitored. An initial tracer experiment was done using an instantaneous injection, which was followed by additional injections of water. Another tracer injection was done when there was a continuous flow of impacted water into the workings. Analysis of the tracer concentration responses at water-filled shafts and at the portal were used to model the flow along the tunnel and estimate several hydraulic parameters. Waters in these settings are mixtures of components with different residence times, so, qualitative tritium data were used to evaluate residence times of decades. The combined injected tracer and tritium data as well as other geochemical data were used to infer the nature of flow and recharge into the tunnel.
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Demchak, J., Morrow, T., Skousen, J., Donovan, J. J., & Rose, A. W. (2001). Treatment of acid mine drainage by four vertical flow wetlands in Pennsylvania Evolution and remediation of acid-sulfate groundwater systems at reclaimed mine-sites. Geochemistry – Exploration, Environment, Analysis, 1(1), 71–80.
Abstract: Acid mine drainage (AMD) is a serious problem in many watersheds where coal is mined. Passive treatments, such as wetlands and anoxic limestone drains (ALDs), have been developed, but these technologies show varying treatment efficiencies. A new passive treatment technique is a vertical flow wetland or successive alkalinity producing system (SAPS). Four SAPS in Pennsylvania were studied to determine changes in water chemistry from inflow to outflow. The Howe Bridge SAPS removed about 130 mg l (super -1) (40%) of the inflow acidity concentration and about 100 mg l (super -1) (60%) iron (Fe). The Filson 1 SAPS removed 68 mg l (super -1) (26%) acidity, 20 mg l (super -1) (83%) Fe and 6 mg l (super -1) (35%) aluminium (Al). The Sommerville SAPS removed 112 mg l (super -1) (31%) acidity, exported Fe, and removed 13 mg l (super -1) (30%) Al. The McKinley SAPS removed 54 mg l (super -1) (91%) acidity and 5 mg l (super -1) (90%) Fe. Acid removal rates at our four sites were 17 (HB), 52 (Filson1), 18 (Sommerville) and 11 (McKinley) g of acid per m (super 2) of surface wetland area per day (g/m (super 2) d (super -1) ). Calcium (Ca) concentrations in the SAPS effluents were increased between 8 and 57 mg l (super -1) at these sites. Equilibrators, which were inserted into compost layers to evaluate redox conditions at our sites, showed that reducing conditions were generally found at 60 cm compost depths and oxidized conditions were found at 30 cm compost depths. Deeply oxidized zones substantiated observations that channel flow was occurring through some parts of the compost. The Howe Bridge site has not declined in treatment efficiency over a six year treatment life. The SAPS construction costs were equal to about seven years of NaOH chemical treatment costs and 30 years of lime treatment costs. So, if the SAPS treatment longevity is seven years or greater and comparable effluent water quality was achieved, the SAPS construction was cost effective compared to NaOH chemical treatment. Construction recommendations for SAPS include a minimum of 50 cm of compost thickness, periodic replacement or addition of fresh compost material, and increasing the number of drainage pipes underlying the limestone.
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Dempsey, B. A., & Jeon, B. - H. (2001). Characteristics of sludge produced from passive treatment of mine drainage. Geochem.-Explor. Environ. Anal., 1(1), 89–94.
Abstract: In the 1994 paper by Brown, Skousen & Renton it was argued that settleability and wet-packing density were the most important physical characteristics of sludge from treatment of mine drainage. These characteristics plus zeta-potential, intrinsic viscosity, specific resistance to filtration, and coefficient of compressibility were determined for several sludge samples from passive treatment sites and for several sludge samples that were prepared in the laboratory. Sludge from passive systems had high packing density, low intrinsic viscosity, low specific resistance to filtration and low coefficient of compressibility compared to sludge that was produced after addition of NaOH.
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Diz, H. R. (1997). Chemical and biological treatment of acid mine drainage for the removal of heavy metals and acidity. Ph.D. thesis, Virginia Polytechnic Institute and State University,, Blacksburg.
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